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bpo-39434: Improve float __floordiv__ performance and error message #18147

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merged 1 commit into from Jan 30, 2020
Merged

bpo-39434: Improve float __floordiv__ performance and error message #18147

merged 1 commit into from Jan 30, 2020
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corona10 commented Jan 23, 2020 •
edited by bedevere-bot

https://bugs.python.org/issue39434
@corona10 corona10 force-pushed the corona10:bpo-39434 branch from d422a3e to 1545084 Jan 23, 2020
@corona10 corona10 removed the DO-NOT-MERGE label Jan 23, 2020
@corona10 corona10 changed the title [WIP] bpo-39434: Add float __floordiv__ fast path bpo-39434: Add float __floordiv__ fast path Jan 23, 2020
@corona10 corona10 requested review from vstinner and mdickinson Jan 23, 2020
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corona10 commented Jan 23, 2020

@mdickinson, @vstinner
If this proposal is accepted, I am going to add news.d since the error message is changed.
@corona10 corona10 removed the skip news label Jan 23, 2020
@corona10 corona10 changed the title bpo-39434: Add float __floordiv__ fast path bpo-39434: Remove unnecessary logic of float __floordiv__ Jan 23, 2020
@corona10 corona10 force-pushed the corona10:bpo-39434 branch from 1940a5d to b83bba9 Jan 23, 2020
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Neat trick: I was worried about duplicated code (see the issue discussion), but it seems we can rely on the compiler to inline _float_div_mod and then strip out the redundant stuff.

LGTM
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mdickinson commented Jan 23, 2020

Is there benefit to applying the same approach to float_rem? Apart from the possibility of a performance boost, it looks as though it would actually make the code simpler (removing existing duplication) and safer. And for floats, % is possibly used more often than // (for argument reduction, for example).
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mdickinson commented Jan 23, 2020

Apart from the possibility of a performance boost,

Sorry, of course that doesn't apply, since float_rem is already special-cased and doesn't go via divmod.
@corona10 corona10 changed the title bpo-39434: Remove unnecessary logic of float __floordiv__ bpo-39434: Improve float __floordiv__ performance and update error message Jan 24, 2020
@corona10 corona10 changed the title bpo-39434: Improve float __floordiv__ performance and update error message bpo-39434: Improve float __floordiv__ performance and error message Jan 24, 2020
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bpo-39434: Improve float __floordiv__ performance and error message
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@corona10 corona10 force-pushed the corona10:bpo-39434 branch from b83bba9 to 269e8fe Jan 24, 2020
@corona10 corona10 requested a review from pablogsal Jan 27, 2020
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corona10 commented Jan 28, 2020

@vstinner @pablogsal If you don't mind can you please take a look? :)
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mdickinson commented Jan 30, 2020

I've done some manual testing as well as reviewing. Still LGTM.
@mdickinson mdickinson merged commit 8d49f7c into python:master Jan 30, 2020
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Azure Pipelines PR #20200124.5 succeeded
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bedevere/issue-number Issue number 39434 found
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bedevere/news News entry found in Misc/NEWS.d
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